The invention relates to a method for detecting an operating parameter of a power tool comprising an internal combustion engine, in particular, of a portable, hand-held power tool with a reciprocating piston engine such as a two-stroke engine, a four-stroke engine or the like. The internal combustion engine comprises at least one cylinder and a crankcase, and a combustion chamber is defined in the cylinder and delimited by a piston, wherein the piston drives in rotation a crankshaft supported rotatably in the crankcase. An intake is provided that supplies combustion air to the combustion chamber and an exhaust is provided for removing combustion gases from the combustion chamber. A signal generator is provided that is driven in rotation by the crankshaft and emits sequential alternating voltage signals for one crankshaft revolution.
Modern internal combustion engines as they are used e.g. in connection with hand-held portable power tools are controlled by complex ignition devices that take into consideration different operating parameters of the internal combustion engine. These different operating parameters of the internal combustion engine must be provided to the control unit for which purpose engine speed sensors, throttle sensors, load sensors, knocking sensors and other devices are required. The plurality of sensors is technically complex, expensive, and entails many error sources. In addition, the required cable arrangement is problematic because in case of small-size power tools with internal combustion engines considerable thermal loads occur.